In drilling a borehole in the earth, such as in exploration and recovery of hydrocarbons, a drill bit is connected on the lower end of an assembly of drill pipe sections connected end-to-end to form a “drill string”. In some cases the drill string and bit are rotated by a drilling table at the surface, and in other cases the drill bit may be rotated by a downhole motor within the drill string above the bit, while remaining portions of the drill string remain stationary. In most cases, the downhole motor is a progressive cavity motor that derives power from drilling fluid (sometimes referred to as “mud”) pumped from the surface, through the drill string, and then through the motor (hence the motor may also be referred to as a “mud motor”).
It is common in the drilling industry to rent downhole equipment, such as mud motors, with the agreement that the billable time will be the total accumulated operating time of the motor. While in most cases the drilling operators correctly report total accumulated operating time, in some cases the operating time is under-reported.